Pietrock Michael, Goater Cameron P
Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada T1 K 3M4.
J Parasitol. 2005 Aug;91(4):854-6. doi: 10.1645/GE-473R.1.
The effect of cadmium (Cd) exposure on infectivity of cercariae of 2 trematode species (Ornithodiplostomum ptychocheilus and Posthodiplostomum minimum) to their second intermediate fish host was evaluated. Individual fathead minnows (Pimephales promelas) were exposed to cercariae that had been treated with Cd solutions at concentrations of 0, 2, 20, or 200 microg/L for 2 hr. Two weeks later, the numbers of encysted metacercariae in the brain (O. ptychocheilus) and body cavity (P. minimum) of the fish were evaluated. ANOVA analyses indicated a strong negative effect of Cd concentration on cercaria infectivity. The species x Cd concentration interaction was not significant, indicating that the magnitude of Cd-induced reduction in infectivity was similar between O. ptychocheilus and P. minimum. The results show that short-term exposure to Cd, even at low concentrations, interferes with transmission processes that affect the recognition and penetration of cercariae, the migration and survival of metacercariae within the second intermediate host, or both.
评估了镉（Cd）暴露对2种吸虫（褶盘双腔吸虫和微小后双腔吸虫）尾蚴感染其第二中间宿主鱼类的影响。将单个黑头呆鱼（肥头鲦鱼）暴露于分别用浓度为0、2、20或200微克/升的Cd溶液处理2小时的尾蚴中。两周后，评估鱼脑中（褶盘双腔吸虫）和体腔中（微小后双腔吸虫）包囊后尾蚴的数量。方差分析表明Cd浓度对尾蚴感染性有强烈的负面影响。物种×Cd浓度的交互作用不显著，表明Cd诱导的感染性降低幅度在褶盘双腔吸虫和微小后双腔吸虫之间相似。结果表明，即使是短期暴露于低浓度的Cd，也会干扰影响尾蚴识别和穿透、后尾蚴在第二中间宿主体内迁移和存活的传播过程，或两者皆有。
